Extensional set

Okay kiddo, let me explain what an extensional set is. Have you ever played with a box full of toys? Imagine that the box is like a set. It has different things in it, like cars, dolls, action figures, and building blocks. These things are called the members of the set.

Now, an extensional set is when we define the set by listing out all of its members. So, if we were talking about the box of toys, an extensional definition of the set would be to list out all of the toys in the box: "The set of toys in the box includes a red car, a Barbie doll, a Spiderman action figure, and lots of building blocks."

This is different from an intentional definition of a set. An intentional definition would be saying something like, "The set of toys in the box includes all of the toys that are red." See the difference?

So basically, an extensional set is a way to define a set by naming all of its members. It's like making a list of everything in the box of toys. Pretty simple, right?